There are people here who state "both are clearly and obviously unconstitutional" with regard to certain gun laws.
And it never occurs to them to ask "according to who?"

GCA'68 repeatedly uses the phrase like "(1) to receive, possess, or transport any firearm or ammunition in or affecting interstate or foreign commerce; or (2) to receive any firearm or ammunition which has been shipped or transported in interstate or foreign commerce."

The government is claiming authority to regulate guns via the Commerce Clause (in Article I, Section 8.) The 2nd Amendment (all the amendments, actually) modifies the body of the Constitution -- if the government ever had any authority under the commerce clause to regulate arms (which is debatable), the 2nd Amendment removes that authority. Only a dishonest "what the meaning of 'is' is" -type reading could interpret it differently.

__________________
"The only way to stop a bad guy with a gun is with a good guy with a gun"